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WO2014179036A1 - Régulation de la pression du procédé lors de la synthèse du nylon - Google Patents

Régulation de la pression du procédé lors de la synthèse du nylon Download PDF

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Publication number
WO2014179036A1
WO2014179036A1 PCT/US2014/034116 US2014034116W WO2014179036A1 WO 2014179036 A1 WO2014179036 A1 WO 2014179036A1 US 2014034116 W US2014034116 W US 2014034116W WO 2014179036 A1 WO2014179036 A1 WO 2014179036A1
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WIPO (PCT)
Prior art keywords
liquid
coupled
vacuum pump
port
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/US2014/034116
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English (en)
Inventor
Thomas A. Micka
Charles R. KELMAN
John P. POINSATTE
Gary R. West
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INVISTA TECHNOLOGIES Sarl
Invista Technologies SARL USA
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INVISTA TECHNOLOGIES Sarl
Invista Technologies SARL USA
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Publication of WO2014179036A1 publication Critical patent/WO2014179036A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/04—Preparatory processes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
    • C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
    • C08G69/28—Preparatory processes

Definitions

  • Polyamides are manufactured using a process in which a diamine (e.g., hexamethylene-l,6-diamine) and a dicarboxylic acid (e.g. , adipic acid), sometimes in the form of an ammonium carboxylate salt of the two components in water, are polymerized under condensation polymerization conditions (e.g. , at temperatures ranging from 180°C to 300°C).
  • the condensation reaction produces the polyamide (e.g., nylon 6,6) and water as a byproduct.
  • an early step in the process involves concentrating the ammonium carboxylate salt solution before transferring the solution into a reactor.
  • the process of concentrating the ammonium carboxylate salt solution generates water, which is vented into the atmosphere as steam or is condensed to form liquid water.
  • the condensed liquid water is then typically discarded into the sewage system of the polyamide-producing facility.
  • a continuous polymerization manufacturing process can include a vent condenser downstream of the finisher.
  • a gaseous mixture can be drawn from the vent condenser using a jet ejector.
  • a jet ejector generates a vacuum by passing steam through a venturi device. Large amounts of steam are passed in order to draw a sufficient vacuum. In one example, approximately 450 Kg/hour of steam is required to generate sufficient vacuum. Steam is costly to generate and a jet ejector generates a substantial volume of waste steam.
  • output from a jet ejector can include contaminants drawn from the vent condenser. The contaminants may need to be removed, thus incurring additional costs.
  • Typical polymer synthesis processes are problematic in that they rely heavily on process steam.
  • Process steam can be economically costly in terms of production costs and environmentally costly in terms of generating waste and consuming limited resources.
  • process-steam based systems cannot be controlled in a manner to produce high volume, good quality product.
  • An example of the present subject matter includes a liquid ring vacuum pump.
  • a liquid ring vacuum pump (LRVP) generates a vacuum by rotating vanes in an eccentric cavity in a housing. The vanes are fixedly attached to a rotating shaft. A liquid ring at the periphery of the eccentric cavity provides a seal with very low frictional resistance.
  • the sealing liquid ring is provided by water, oil, or other fluid. In various examples, the sealing fluid is drawn from the vacuum or provided at a port on the housing of the pump.
  • the LRVP can be a single-stage or multiple- stage pump.
  • An example of the present subject matter uses a LRVP for controlling the manufacturing process.
  • a LRVP can use a once-through seal fluid supply or recirculating seal fluid supply, or a blended seal fluid supply.
  • An example system using a LRVP can be operated economically and controlled with good precision.
  • An example of the present subject matter uses a LRVP to generate a vacuum for drawing the gaseous mixture from a vent condenser associated with a finisher in a continuous polymerization process.
  • the LRVP of the present subject matter can provide a vacuum with substantially less energy expenditure as compared to that associated with generating steam used in a jet ejector.
  • the LRVP of the present subject matter can generate substantially less impurities in a polymer mixture during operation, such as less iron (which can be a gelation catalyst), as compared to methods that form a vacuum using equipment having a greater amount of metal-on-metal contact in the polymer mixture, such as a mechanical vane pump.
  • the lower amount of impurities, such as iron, generated during operation can allow a polymerization process including the LRVP to experience less gelation, providing high quality product and a greater proportion of on-stream time, as compared to polymerization processes including a mechanical vane pump or other pumps with greater metal-on-metal contact in the polymer mixture.
  • FIG. 1 illustrates a schematic representation of a system for
  • FIG. 2 illustrates a portion of a polyamide production system, according to one example.
  • FIG. 3 illustrates a portion of a polyamide production system, according to one example.
  • FIG. 4 illustrates a portion of a polyamide production system, according to one example.
  • FIG. 5 illustrates a flow chart of a method for manufacturing polyamide, according to one example.
  • dicarboxylic acid refers broadly to C 4 -C 18 ⁇ , ⁇ -dicarboxylic acids. Within this term are subsumed C 4 -C 10 ⁇ , ⁇ -dicarboxylic acid and C 4 -C 8 ⁇ , ⁇ -dicarboxylic acids. Examples of dicarboxylic acids encompassed by C4-C 18 ⁇ , ⁇ -dicarboxylic acids include, but are not limited to, succinic acid
  • the C 4 - Ci 8 ⁇ , ⁇ -dicarboxylic acid are adipic acid, pimelic acid or suberic acid.
  • the C 4 -C 18 ⁇ , ⁇ -dicarboxylic acid is adipic acid.
  • diamine refers broadly to C 4 -C 18 , ⁇ - diamines. Within this term are subsumed C 4 -C 10 ⁇ , ⁇ -diamines and C 4 -C 8 ⁇ , ⁇ - diamines. Examples of diamines encompassed by C 4 -C 18 ⁇ , ⁇ -diamines include, but are not limited to, butane- 1,4-diamine, pentane-l,5-diamine, and hexane-1,6- diamine, also known as hexamethylenediamine. In some examples, the C 4 -C 18 , ⁇ - diamine is hexamethylenediamine.
  • adipic acid in combination with hexamethyelene diamine is contemplated herein.
  • polyamide refers broadly to polyamides such as nylon 6, nylon 7, nylon 11, nylon 12, nylon 6,6, nylon 6,9; nylon 6,10, nylon 6,12, or copolymers thereof.
  • the polymer manufactured by executing a method or operating a system is a polyamide.
  • the polyamide can be synthesized from a linear dicarboxylic acid and a linear diamine or synthesized from an oligomer formed from a linear dicarboxylic acid and a linear diamine.
  • the polyamide can include nylon 6,6.
  • the dicarboxylic acid can have the structure HOC(0)-R 1 -C(0)OH, wherein R 1 is a C 1 -C 15 alkylene group, such as a methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, or decylene group.
  • R 1 is a C 1 -C 15 alkylene group, such as a methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, or decylene group.
  • the diamine can have the structure H 2 N-R 2 -NH 2 , wherein R 2 is a Ci-
  • Ci 5 alkylene group such as a methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, or decylene group.
  • FIG. 1 illustrates example system 10 for producing a polyamide, and in particular for producing nylon 6,6.
  • System 10 includes various components that heat and evaporate water from a reaction mixture including an oligomer formed from a linear dicarboxylic acid and a linear diamine.
  • the oligomer formed from the linear dicarboylic acid and the linear diamine can be a polyamide salt, such as a nylon salt formed by the combination of adipic acid and hexamethylene diamine.
  • the oligomer can include a combination of a single molecule of diacid with a single molecule of diamine, such as a hexamethylene diammonium adipate.
  • the oligomer can be the product of one or more than one molecule of diacid with one or more than one molecule of diamine.
  • the mixture including the oligomer can also include unreacted diamine and unreacted diacid.
  • the mixture including the oligomer can include oligomers of various length in any suitable proportion.
  • the heating and evaporation of the mixture including the oligomer can be sufficient to remove at least some water from the mixture.
  • the water removed can be at least one of water that was originally present in the mixture, water that is generated by the reaction of diacid with diamine to form an amide, water that is generated by the reaction of diacid or diamine with an oligomer to form an amide, and water that is generated by the reaction of one oligomer with another to form an amide.
  • System 10 can include a reservoir 12 configured to contain an aqueous solution of a solvent (e.g., water) in a liquid or substantially liquid phase and a mixture of the dicarboxylic acid and the diamine, an oligomer formed therefrom (e.g. salt), or a combination thereof.
  • Reservoir 12 can be used to mix or store an aqueous solution of an ammonium carboxylate salt.
  • the dicarboxylic acid and the diamine can be added to reservoir 12 in a substantially equimolar ratio.
  • the starting materials or aqueous solution can be preheated before being introduced to the reservoir 12, such as with a preheater, or the aqueous solution can be heated within the reservoir 12, such as with a heater or with steam, such as steam formed in another portion of the system 10.
  • the reaction mixture can be transferred from reservoir 12 to evaporator 14 via line 16.
  • Evaporator 14 can heat the reaction mixture and evaporate water therefrom, pushing the equilibrium further toward the polyamide product.
  • the water evaporated from the reaction mixture in evaporator 14 can exit evaporator 14 via line 8.
  • the reaction mixture can be heated to any suitable temperature within evaporator 14, such as about 100-230 °C, or 100-150 °C, or about 100 °C or less, or about 110 °C, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220 °C, or about 230 °C or more.
  • the reaction mixture exiting evaporator 14 via line 22 can have any suitable wt water, such as about 5-50 wt water, or about 25-35 wt% water, or about 25 wt% or less, 26 wt%, 27, 28, 29, 30, 31, 32, 33, 34 wt or about 35 wt or more water.
  • the reaction mixture in evaporator 14 can be transferred via line 22 to reactor 18.
  • Reactor 18 can heat the reaction mixture and evaporate water therefrom, pushing the equilibrium further toward the polyamide product.
  • the water that is evaporated from the reaction mixture in reactor 18 can exit via line 26 and enter condenser 24 where it can be condensed to form liquid water exiting condenser 24 in line 28.
  • the liquid water in line 28 can be suitably treated and reused in the reservoir 12, in other components of the facility, or can be disposed in the sewer.
  • the heat absorbed by condenser 24 can be reused in other components of the facility, such as in a preheater.
  • the reaction mixture can be heated to any suitable temperature within reactor 18, such as about 150-400 °C, or about 250-350 °C, or about 250-310 °C, or about 200 °C or less, or about 210 °C, 220, 230, 240, 250, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 320, 330, 340 °C, or about 350 °C or more.
  • the reaction mixture exiting reactor 18 via line 32 can have any suitable wt% water, such as about 0.000,1 wt to 20 wt , 0.001 to 15 wt , or about 0.01 to 15 wt , or about 0.000,1 wt or less, or about 0.001 wt , 0.01, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,12, 13, 14, 15, 16, 17, 18, 19 wt%, or about 20 wt% or more.
  • the reaction mixture in reactor 18 can be transferred via line 32 to flasher 30.
  • Flasher 30 can heat the reaction mixture and evaporate water therefrom, pushing the equilibrium further toward the polyamide product.
  • Flasher 30 can include at least one relatively long serpentine tube. Within flasher 30, the pressure can gradually decrease as the reaction mixture travels downstream. At the elevated temperature within flasher 30, the gradually reducing pressure exerted on the reaction mixture removes water from the reaction mixture in the form of flashed-off steam. As the steam flashes off from the reaction mixture, the first polyamide polymer can undergo further polymerization to form a second polyamide polymer. At an outlet of flasher 30, a two phase mixture of gaseous steam and the reaction mixture can be formed.
  • the reaction mixture can be heated to any suitable temperature within flasher 30, such as about 150-400 °C, or about 250-350 °C, or about 250-310 °C, or about 200 °C or less, or about 210 °C, 220, 230, 240, 250, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 320, 330, 340 °C, or about 350 °C or more.
  • any suitable temperature within flasher 30 such as about 150-400 °C, or about 250-350 °C, or about 250-310 °C, or about 200 °C or less, or about 210 °C, 220, 230, 240, 250, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 320, 330, 340 °C, or about 350 °C or more.
  • the reaction mixture exiting flasher 30 via line 34 can have any suitable wt water, such as about 0.000,1 wt to 2 wt , 0.001 to 1 wt , or about 0.01 to 1 wt , or about 0.000,1 wt or less, or about 0.001 wt , 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8 wt , or about 2 wt or more.
  • the reaction mixture in flasher 30 can be transferred via line 34 to finisher 208.
  • Finisher 208 can heat the reaction mixture and evaporate water therefrom, pushing the equilibrium further toward the polyamide product, such that the final desired range of degree of polymerization of the polyamide product is achieved. Finisher 208 can further remove water so that the second polyamide polymer undergoes further polymerization to form a final polyamide polymer having a final desired molecular weight or range of molecular weights. The final desired molecular weight or range of molecular weights chosen can depend on the particular desired properties of the polyamide product. Removing water in finisher 208 can be achieved by applying a high temperature and a vacuum pressure to the reaction mixture.
  • the range of molecular weights of the final polyamide polymer can be controlled.
  • the reaction mixture can be heated to any suitable temperature within finisher 208, such as about 150-400 °C, or about 250-350 °C, or about 250-310 °C, or about 200 °C or less, or about 210 °C, 220, 230, 240, 250, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 320, 330, 340 °C, or about 350 °C or more.
  • the reaction mixture exiting finisher 208 can have any suitable wt water, such as about 0.000,1 wt to 2 wt , 0.001 to 1 wt , or about 0.01 to 1 wt , or about 0.000,1 wt or less, or about 0.001 wt%, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8 wt , or about 2 wt or more water.
  • any suitable wt water such as about 0.000,1 wt to 2 wt , 0.001 to 1 wt , or about 0.01 to 1 wt , or about 0.000,1 wt or less, or about 0.001 wt%, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6,
  • Discharge from finisher 208 is routed downstream for further processing. Further processing can include adjusting relative viscosity, spinning, and pelletization.
  • the reaction mixture in finisher 208 includes polyamide having a desired range of degree of polymerization, and in one example, is at a temperature of approximately 280° C.
  • Relative viscosity is a measure of the ratio of solution and solvent viscosities measured in a capillary viscometer at a particular temperature.
  • relative viscosity is the ratio of viscosity (in centipoises) at 25° C of 8.4% by weight solution of polyamide in 90% formic acid (90% by weight formic acid and 10% by weight water) to the viscosity (in centipoises) at 25° C of 90% formic acid alone.
  • Relative viscosity can be correlated with a measure of molecular weight.
  • relative viscosity is modulated by drawing a controlled vacuum on a vent condenser using a liquid ring vacuum pump.
  • the vent condenser is coupled to finisher 208.
  • Modulating the relative viscosity can include implementing a feedback process using a sensor and a controller coupled to a motor drive for the LRVP.
  • FIG. 2 illustrates system 200A which depicts one example of processing associated with finisher 208 and certain elements downstream of finisher 208.
  • Material from finisher 208 is conveyed to vent condenser 216 using elbow 210.
  • the material flows in a direction denoted by arrow 272.
  • vent condenser 216 includes a vertical column having weir 218 arranged at an upper region.
  • Weir 218 can include an annular wall having an open top and a closed bottom. Water (or other fluid) conveyed into weir 218 can spill over the top and, in this example, is shown as droplets 220 falling into reservoir 224 located at the bottom of vent condenser 216. As shown by arrow 214, water is supplied to weir 218 by valve 212.
  • vent condenser 216 can include a spray nozzle. The spray nozzle (not shown in the example illustrated) can dispense a stream of water, water droplets, or atomized water in an upper region of vent condenser 216.
  • vent condenser 216 affects the turbulence in vent condenser 216. For example, with a high flow rate (at valve 212), splashing can produce more aerosols in the gaseous mixture above reservoir 224, and thus affect downstream equipment.
  • Water in reservoir 224 has fluid level 222.
  • Discharge from reservoir 224 is conveyed to collection tank 232 by line 228 A (sometimes referred to as a barometric line).
  • Collection tank 232
  • weir 234 (sometimes referred to as a hot well) includes weir 234.
  • Weir 234 retains material in collection tank 232 until a volume exceeds that depicted by level 230 (established by the height of weir 234).
  • Water at level 236 drains from collection tank 232 by port 238 on line 240 as shown by arrow 242.
  • Line 242 can be coupled to a tank (not shown) or a sanitary sewer system (not shown).
  • Gaseous material in vent condenser 216 is carried by vacuum in line 226.
  • Line 226 is coupled to vent condenser 216 at a position above fluid level 222.
  • Liquid ring vacuum pump 246A draws a vacuum in line 226 and discharges output to filter 252A.
  • Filter 252A can include a stack scrubber.
  • the discharge from filter 252 A is vented to atmosphere by line 254 in a direction represented by arrow 256.
  • the amount of vacuum drawn by liquid ring vacuum pump 246A is determined by the rotational speed of shaft 248A.
  • Shaft 248A is coupled to electric motor 250A in this example.
  • Motor 250A is powered by metered line service (not shown) and is controlled by controller 258 A.
  • motor 250A has a power rating of approximately three horsepower.
  • motor 250A is non-electric and other means of controlling the shaft speed are provided.
  • controller 258A includes computer 270 coupled to sensor 266.
  • Computer 270 includes processor 260, memory 262, and interface 264.
  • Memory 262, interface 264, and sensor 266 are in communication with processor 260.
  • Processor 260 is configured to execute instructions to implement an algorithm for controlling LRVP 246A.
  • the algorithm can include operating motor 250A based on a signal from sensor 266.
  • Memory 262 provides storage for the instructions and data associated with controlling LRVP 246A.
  • Interface 264 can include a keyboard, a touchpad, a screen, a printer, a network interface, or other component configured to allow a user to monitor or control performance of LRVP 246 A.
  • Sensor 266 is coupled to 270 by channel 268.
  • Channel 268 can include a wired or wireless communication link.
  • Sensor 266 can include a pressure sensor, a vacuum sensor, a flow sensor, a temperature sensor, a level sensor, a clock, a load sensor, or other component configured to provide a signal on which operation of LRVP 246 A can be controlled.
  • the amount of vacuum drawn can be controlled by modulating a valve associated with LRVP 246A.
  • a valve can be configured to bypass LRVP 246A or configured to vent either the low (vacuum) side or the high (pressure) side of LRVP 246 A.
  • the valve position can be controlled by processor 260 based on a signal from sensor 266.
  • the LRVP 246A can draw any suitable volume of gas from the finisher.
  • the liquid ring vacuum pump can draw about 10 m /h to about 50,000 m 3 /h, about 20 m 3 /h to about 30,000 m 3 /h, about 50 m 3 /h to about 20,000 m 3 /h, or about 10 m 3 /h or less, or about 20, 30, 40, 50, 75, 100, 125, 150, 175, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1,000, 1,500, 2,000, 2,500, 5,000, 10,000, 20,000, 30,000, 40,000, or about 50,000 m 3 /h.
  • the LRVP 246A can be made of any suitable material or
  • LRVP 246A can include stainless steel, such as austenitic steel, ferritic steel, martensitic steel, and combinations thereof in any suitable proportion.
  • stainless steels can include any suitable series of stainless steel, such as for example 440A, 440B, 440C, 440F, 430, 316, 409, 410, 301, 301LN, 304L, 304LN, 304, 304H, 305, 312, 321, 321H, 316L, 316, 316LN, 316Ti, 316LN, 317L, 2304, 2205, 904L, 1925hMo/6MO, 254SMO.
  • Austenitic steels can include 300 series steels, for example having a maximum of about 0.15% carbon, a minimum of about 16% chromium, and sufficient nickel or manganese to retain an austenitic structure at substantially all temperatures from the cryogenic region to the melting point of the alloy.
  • Austenitic steel can include, for example, 304 and 316 steel, such as 316L steel.
  • LRVP 246 A can include corrosion-resistant materials.
  • corrosion-resistant materials can include superalloys, such as nickel-copper alloys containing small amounts of iron and trace amounts of other elements such as MONEL ® 400, precipitation- strengthened nickel- iron-chromium alloys such as INCOLOY ® brand alloys, for example INCOLOY ® 800 series, or austenitic nickel-chromium-based INCONEL ® brand alloys, or nickel- chromium-molybdenum alloys such as HASTELLOY ® brand alloys, for example, HASTELLOY ® G-30 ® .
  • corrosion-resistant materials can include any suitable corrosion-resistant material, such as super austenitic stainless steels (e.g.
  • duplex stainless steels e.g. 2205
  • super duplex stainless steels e.g. 2507
  • nickel-based alloys e.g. alloy C276, C22, C2000, 600, 625, 800, 825
  • titanium alloys e.g. grade 1, 2, 3
  • zirconium alloys e.g. 702
  • Hasteloy 276, duplex 2205 super duplex 2507, Ebrite 26-1, Ebrite 16-1
  • Hasteloy 276, Duplex 2205 316 SS, 316L and 304SS
  • zirconium zirconium clad 316, ferralium 255, or any combination thereof.
  • LRVP 246 A can reduce costs associated with a jet steam ejector, such as the cost of water and the cost of generating steam. Despite the cost of electricity for the motor 250A, LRVP 246A can provide significant energy cost savings compared to a jet steam ejector. For example, LRVP 246A can provide an energy cost that is 0.01% to 95% of the energy cost of a steam ejector, or about 1% to about 80%, or about 0.01% or less, about 0.1, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90%, or about 95% of the energy cost of a steam ejector.
  • LRVP 246A can be configured to have less metal-on-metal contact in the polymer mixture compared to other equipment, such as a mechanical vane pump. For example, by using a liquid ring as a seal, LRVP 246A avoids metal-to- metal wear between impeller tips and the inside of the pump housing.
  • LRVP 246A can have about 0.000,1 ppm to about 200 ppm iron in the polymer reaction mixture exiting the pump, or about 0.001 ppm to about 25 ppm iron, or about 0.000,1 ppm or less, 0.000,5, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, or about 200 ppm or more.
  • the ppm iron in the reaction mixture exiting the pump can be any suitable amount less than the ppm iron in a corresponding reaction mixture exiting a mechanical vane pump, such as about 0.01% to 95%, or about 1% to about 80%, or about 0.01% or less, about 0.1, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90%, or about 95%.
  • Iron can be a gelation catalyst; reducing iron content can reduce gel production.
  • the gel produced per day downstream of the pump can be any suitable amount, and can be less than that produced by a corresponding reaction mixture exiting a mechanical vane pump approximately proportionally to the decrease in iron content the reaction mixture emerging from the pump, such as about 0.000,1 Kg gel/day to about 100 Kg/gel/day, about 0.001 Kg gel/day to about 50 Kg gel/day, or about 0.000,1 Kg gel/day, 0.000,5, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, or about 100 Kg/gel/day.
  • FIG. 3 illustrates system 200B which depicts one example of processing associated with finisher 208 and certain elements downstream of finisher 208.
  • Material from finisher 208 is conveyed to vent condenser 216 using elbow 210.
  • the material flows in a direction denoted by arrow 272.
  • vent condenser 216 includes a vertical column having weir 218 arranged at an upper region.
  • Weir 218 can include an annular wall having an open top and a closed bottom.
  • Water (or other fluid) conveyed into weir 218 can spill over the top and, in this example, is shown as droplets 220 falling into reservoir 224 located at the bottom of vent condenser 216.
  • water is supplied to weir 218 by valve 308.
  • Water in reservoir 224 has fluid level 222.
  • Line 228B carries water from reservoir 224 to pump 302.
  • Pump 302 carries discharge from reservoir 224 to filter 304.
  • Valve 302 draws from line 228B coupled to reservoir 224.
  • Valve 310 allows discharge of excess water as shown at arrow 312. Water discharged from valve 310 can be discharged to a tank (not shown) or a sanitary sewer system (not shown). Valve 310 can be automatically modulated to control a water level recirculated by pump 302. Filter 304 is in series with cooler 306 and valve 308.
  • Gaseous material in vent condenser 216 is carried by vacuum in line 226.
  • Line 226 is coupled to vent condenser 216 at a position above fluid level 222.
  • Liquid ring vacuum pump 246B draws a vacuum in line 226 and discharges output to filter 252B.
  • Filter 252B can include a stack scrubber.
  • the discharge from filter 252B is vented to atmosphere by line 254 in a direction represented by arrow 256.
  • the amount of vacuum drawn by liquid ring vacuum pump 246B is determined by the rotational speed of shaft 248B.
  • Shaft 248B is coupled to electric motor 250B in this example.
  • Motor 250B is powered by metered line service (not shown) and is controlled by controller 258B.
  • Controller 258B can include an analog processor or a digital processor.
  • controller 258B includes a processor 260, a memory 262, an interface 264, and a sensor 266.
  • FIG. 4 illustrates system 200C which depicts one example of processing associated with finisher 208 and certain elements downstream of finisher 208.
  • Material from finisher 208 is conveyed to vent condenser 216 using elbow 210.
  • the material flows in a direction denoted by arrow 272.
  • vent condenser 216 includes a vertical column having weir 218 arranged at an upper region.
  • Weir 218 can include an annular wall having an open top and a closed bottom.
  • Water (or other fluid) conveyed into weir 218 can spill over the top and, in this example, is shown as droplets 220 falling into reservoir 224 located at the bottom of vent condenser 216.
  • water is supplied to weir 218 by line 408, valve 402, and line 404, as shown by arrow 412 and arrow 406.
  • Supply water as shown by arrow 412, can include demineralized water.
  • Water in reservoir 224 has fluid level 222. Discharge from reservoir 224 is drained as shown at arrow 428 using line 228C.
  • Line 420 is coupled at a first end to vent condenser 216 (at a position above fluid level 222) and coupled at a second end to vessel 416.
  • Vessel 416 can be viewed as a vapor-liquid separator.
  • Vessel 416 sometimes referred to as a knockout pot, has an upper discharge port coupled to vacuum line 418.
  • Line 418 carries a gaseous mixture from vessel 416 (as shown at arrow 432), and thus, draws a vacuum from vent condenser 216 by way of line 420.
  • Process steam is condensed in vessel 416 and the resulting water is drained by line 426 and is carried away as shown at arrow 428. Water is supplied to vessel 416 by line 408 as shown at arrow 434.
  • Liquid ring vacuum pump 246C draws a vacuum in line 418 and discharges output to filter 252C.
  • Filter 252C can include a stack scrubber.
  • the discharge from filter 252C is vented to atmosphere by line 254 in a direction represented by arrow 256. Water is drained from filter 252C by line 424 in the direction as shown by arrow 422.
  • Seal fluid for LRVP 246C is supplied by line 436 with flow in the direction indicated by arrow 438.
  • seal fluid includes water and as such, line 436 can be coupled to line 408 or to another supply line.
  • the seal fluid for LRVP 246A and LRVP 246B, respectively is supplied by vent condenser 216, however, in other examples (such as shown in FIG. 4 at LRVP 246C), a separate supply line (e.g., line 436) provides a seal fluid to the vacuum pump 246C.
  • Valve 414 is coupled at a first end to line 418 and at a second end to discharge from line 254. Valve 414 can be modulated to bypass LRVP 246C and thus, control vacuum drawn from vessel 416. [0070] The amount of vacuum drawn by LRVP 246C is determined by the rotational speed of shaft 248C. Shaft 248C is coupled to electric motor 250C in this example. Motor 250C is powered by metered line service (not shown) and is controlled by controller 258C.
  • Controller 258C can include an analog processor or a digital processor.
  • controller 258C includes a processor 260, a memory 262, an interface 264, and a sensor 266.
  • FIG. 5 illustrates a flow chart of method 500 for manufacturing polyamide.
  • Method 500 at 510, includes producing a gaseous mixture above a reservoir 224.
  • the reservoir 224 can include condensation in a vent condenser 216 coupled to a polymerization finisher 208 in a continuous polyamide synthesis system.
  • method 500 includes drawing the gaseous mixture using a vacuum pump 246C.
  • the vacuum pump 246C can include an electric motor 250C driven LRVP 246C.
  • the vacuum level, and therefore the gaseous mixture removal rate, can be determined based on a speed of the rotary shaft 248C of the LRVP 246C.
  • the drive motor 250C for the LRVP 246C can be controlled or modulated using a controller 258C.
  • the controller 258C can include an analog circuit or digital processor.
  • the LRVP 246C can be controlled by software that implements an algorithm stored as instructions in a memory 262.
  • the algorithm uses a sensor signal to control the LRVP 258C.
  • a sensor signal can be generated from a sensor 266 responsive to a pressure, a vacuum, a temperature, a fluid level, a load, or other measured parameter.
  • a LRVP 246C utilizes a ring of fluid to provide a seal.
  • the sealing fluid can be supplied by condensate in the vacuum line 418 or supplied by a separate fluid port.
  • the sealing fluid can include water, an oil, or other fluid.
  • the fluid supplied to the liquid ring of LRVP 246C is heated by the action of the rotating vanes and in one example, the fluid is recovered, filtered, cooled, and recirculated to the LRVP 246C at a flow rate of approximately 1 to 5 gallons per minute.
  • a continuous polymerization process uses clean water for the sealing fluid.
  • a batch polymerization process uses condensate from the process for the sealing fluid.
  • the reactor brings the temperature of the evaporated salt mixture to about 218-250 °C (235 °C), allowing the reactor to further remove water from the heated evaporated salt mixture, bringing the water concentration to about 10 wt , and causing the salt to further polymerize.
  • the reacted mixture is transferred to a flasher at about 60 L/min.
  • the flasher heating the reacted mixture to about 270-290 °C (280 °C), allowing the flasher to further remove water from the reacted mixture, bringing the water concentration to about 0.5 wt , and causing the reacted mixture to further polymerize.
  • the flashed mixture is transferred to a finisher at about 54 L/min.
  • the finisher subjects the polymeric mixture to a vacuum to further remove water, bringing the water concentration to about 0.1 wt , such that the polyamide achieves a suitable final range of degree of polymerization before transferring the finished polymeric mixture to an extruder and a pelletizer.
  • each gelation rate described in the Examples is determined by taking an average of the gelation rate as determined by two methods.
  • the first method while the reaction mixture is still hot the system is drained of the liquid reaction mixture, the system is cooled, diassembled, and visually inspected to estimate the volume of gel therein.
  • the second method while the reaction mixture is still hot the system is drained of liquid reaction mixture, cooled, filled with water, and drained of the water. The volume of water drained from the system is subtracted from the gel- free volume of the system to determine the volume of gel in the system.
  • the density of the gel is estimated at 0.9 g/cm 3 .
  • variable X has the same value throughout the Examples.
  • Example la Comparative Example. Finisher with Barometric Leg
  • the continuous polymerization process is performed. Discharge from the finisher is conveyed to a vent condenser.
  • the vent condenser includes a liquid reservoir fitted with a drain line.
  • the drain line sometimes referred to as a barometric leg, is coupled to a low point in the reservoir.
  • a pump coupled to the barometric leg conveys the liquid from the reservoir to a filter and a cooler and thereafter returns the fluid to a weir and sprayer arrangement located at an upper portion of the vent condenser.
  • a vacuum line is coupled to the vent condenser at a point above the liquid reservoir.
  • the vacuum line is coupled to a 304 austenitic steel mechanical vane pump, which draws 1000 m /h.
  • the vacuum pump discharges to a scrubber and thereafter vents to atmosphere.
  • the electricity to power the mechanical vane pump costs about X per year.
  • the polymer mixture that exits the mechanical vane pump has about 3 ppm iron.
  • the overall amount of gel produced in the system downstream of the vacuum pump is about 0.5 Kg gel per day.
  • Example lb Comparative Example. Finisher with Barometric Leg
  • Comparative Example 1 is followed, but in place of the mechanical vane pump, a 304 austenitic steel steam ejector is used, which draws 1000 m /h.
  • the steam ejector uses 34,000,000 Kg steam per year, costing 3*X per year.
  • the steam requires 1,500,000,000 L of water per year, costing X per year.
  • the steam ejector requires about 4*X per year to operate.
  • Example lc Finisher with Barometric Leg Recirculation and Liquid Ring Vacuum Pump.
  • the continuous polymerization process is performed. Discharge from the finisher 208 is conveyed to a vent condenser 216.
  • the vent condenser 216 includes a liquid reservoir 224 fitted with a drain line.
  • the drain line sometimes referred to as a barometric leg, is coupled to a low point in the reservoir 224.
  • a pump coupled to the barometric leg conveys the liquid from the reservoir 224 to a filter and a cooler 306 and thereafter returns the fluid to a weir 218 and sprayer arrangement located at an upper portion of the vent condenser 216.
  • a vacuum line 420 is coupled to the vent condenser 216 at a point above the liquid reservoir 224.
  • the vacuum line 420 is coupled to a 304 austenitic steel liquid ring vacuum pump 246C, which draws 1000 m /h.
  • the LRVP 246C discharges to a scrubber and thereafter vents to atmosphere.
  • the polymer mixture that exits the LRVP 246C contains about 0.5 ppm iron, which reduces the overall amount of gel produced in the system downstream of the vacuum pump to about 0.1 Kg gel per day, 20% of the rate of gel production in the process including a mechanical vane pump in Comparative Example la, allowing a longer amount of on-stream time between shutdowns and cleanings.
  • the electricity to power the LRVP 246C via the driving motor 250C is about X per year, making the process approximately 400% more efficient than the process including a steam ejector in Comparative Example lb.
  • Example 2a Comparative Example. Finisher with Barometric Leg Discharge and Mechanical Vane Pump.
  • the continuous polymerization process is performed. Discharge from the finisher is conveyed to a vent condenser.
  • the vent condenser includes a liquid reservoir fitted with a drain line.
  • the drain line sometimes referred to as a barometric leg, is coupled to a low point in the reservoir.
  • the liquid in the barometric leg is routed to a collection tank.
  • the collection tank sometimes referred to as a hot well, includes a weir and a discharge port.
  • the collection tank drains to a sanitary sewer.
  • a separate water supply line is coupled to a weir and sprayer arrangement located at an upper portion of the vent condenser.
  • a vacuum line is coupled to the vent condenser at a point above the liquid reservoir.
  • the vacuum line is coupled to a 304 austenitic steel mechanical vane pump, which draws 1000 m /h.
  • the vacuum pump discharges to a scrubber and thereafter vents to atmosphere.
  • the electricity to power the mechanical vane pump costs about X per year.
  • the polymer mixture that exits the mechanical vane pump has about 3 ppm iron.
  • the overall amount of gel produced in the system downstream of the vacuum pump is about 0.5 Kg gel per day.
  • Example 2b Comparative Example. Finisher with Barometric Leg Discharge and Steam Ejector.
  • Comparative Example 2 is followed, but in place of the mechanical vane pump, a 304 austenitic steel steam ejector is used, which draws 1000 m /h.
  • the steam ejector uses 34,000,000 Kg steam per year, costing 3*X per year.
  • the steam requires 1,500,000,000 L of water per year, costing X per year.
  • the steam ejector requires about 4*X per year to operate.
  • Example 2c Finisher with Barometric Leg Discharge and Liquid Ring Vacuum Pump.
  • the continuous polymerization process is performed. Discharge from the finisher 208 is conveyed to a vent condenser 216.
  • the vent condenser 216 includes a liquid reservoir 224 fitted with a drain line.
  • the drain line sometimes referred to as a barometric leg, is coupled to a low point in the reservoir 224.
  • the liquid in the barometric leg is routed to a collection tank 232.
  • the collection tank 232 sometimes referred to as a hot well, includes a weir 234 and a discharge port.
  • the collection tank 232 drains to a sanitary sewer.
  • a separate water supply line is coupled to a weir 218 and sprayer arrangement located at an upper portion of the vent condenser 216.
  • a vacuum line 226 is coupled to the vent condenser 216 at a point above the liquid reservoir.
  • the vacuum line 226 is coupled to a 304 austenitic steel LRVP 246 A, which draws 1000 m 3 /h.
  • the LRVP 246 A discharges to a scrubber and thereafter vents to atmosphere.
  • the polymer mixture that exits the LRVP 246A contains about 0.5 ppm iron, which reduces the overall amount of gel produced in the system downstream of the vacuum pump to about 0.1 Kg per day, 20% of the rate of gel production in the process including a mechanical vane pump in
  • Comparative Example 2a allowing a longer amount of on- stream time between shutdowns and cleanings.
  • the electricity to power the liquid ring vacuum pump via the driving motor 250A costs X per year, making the process approximately 400% more efficient than the process including a steam ejector in Comparative Example 2b.
  • Example 3a Comparative Example. Finisher with Vapor-Liquid Separator and Mechanical Vane Pump.
  • the continuous polymerization process is performed. Discharge from the finisher is conveyed to a vent condenser.
  • the vent condenser includes a liquid reservoir fitted with a drain line.
  • the drain line sometimes referred to as a barometric leg, is coupled to a low point in the reservoir.
  • a vacuum line is coupled to the vent condenser at a point above the liquid reservoir.
  • the vacuum line is coupled to an input port of a vapor-liquid separator. Liquid drawn from a low point of the vapor- liquid separator is routed to a coupling on the barometric leg.
  • a gaseous mixture above the liquid in the vapor- liquid separator is drawn through the vacuum line which is coupled to a 304 austenitic steel mechanical vane pump, which draws 1000 m /h.
  • the vacuum pump discharges to a scrubber and thereafter vents to atmosphere.
  • the electricity to power the mechanical vane pump costs about X per year.
  • the polymer mixture that exits the mechanical vane pump has about 3 ppm iron.
  • the overall amount of gel produced in the system downstream of the vacuum pump is about 0.5 Kg gel per day.
  • a separate water supply line is coupled to a weir and sprayer arrangement located at an upper portion of the vent condenser and to an upper portion of the vapor-liquid separator.
  • Example 3b Comparative Example. Finisher with Vapor- Liquid Separator and Steam Ejector.
  • Comparative Example 3 is followed, but in place of the mechanical vane pump, a 304 austenitic steel steam ejector is used, which draws 1000 m /h.
  • the steam ejector uses 34,000,000 Kg steam per year, costing 3*X per year.
  • the steam requires 1,500,000,000 L of water per year, costing X per year.
  • the steam ejector requires about 4*X per year to operate.
  • Example 3c Finisher with Vapor- Liquid Separator and Liquid Ring Vacuum Pump.
  • the continuous polymerization process is performed. Discharge from the finisher 208 is conveyed to a vent condenser 216.
  • the vent condenser 216 includes a liquid reservoir 224 fitted with a drain line.
  • the drain line sometimes referred to as a barometric leg, is coupled to a low point in the reservoir 224.
  • a vacuum line 420 is coupled to the vent condenser 216 at a point above the liquid reservoir 224.
  • the vacuum line 420 is coupled to an input port of a vapor-liquid separator 416. Liquid drawn from a low point of the vapor-liquid separator is routed to the barometric leg. A gaseous mixture above the liquid in the vapor-liquid separator 416 is drawn through a 304 austenitic steel LRVP 246C
  • a bypass valve 414 couples the intake and output ports of the LRVP 246C.
  • a separate water supply line is coupled to a weir 218 and sprayer arrangement located at an upper portion of the vent condenser 216 and to an upper portion of the vapor-liquid separator 416.
  • the polymer mixture that exits the LRVP 246C contains about 0.5 ppm iron, which reduces the overall amount of gel produced in the system downstream of the vacuum pump to about 0.1 Kg per day, 20% of the rate of gel production in the process including a mechanical vane pump in Comparative Example 3a, allowing a longer amount of on-stream time between shutdowns and cleanings.
  • the electricity to power the liquid ring vacuum pump via the driving motor 250C costs about X per year, making the process approximately 400% more efficient than the process including a steam ejector in Comparative Example 3b.
  • Example 1 can include or use a system for continuous polyamide synthesis, the system can include or use a vent condenser and a vacuum pump.
  • the vent condenser is coupled to a polymerization finisher.
  • the vent condenser has a liquid reservoir and has a vent discharge port above a level of the liquid reservoir.
  • the vacuum pump is coupled to the vent discharge port by an intake line.
  • the vacuum pump has an output port and has a rotary shaft. A gaseous mixture proximate the vent discharge port is removed at a rate determined by a speed of the rotary shaft.
  • the vacuum pump is configured to have a liquid ring seal.
  • Example 2 can include, or optionally be combined with the subject matter of Example 1, to optionally include wherein the rotary shaft is coupled to an electric motor.
  • Example 3 can include, or optionally be combined with the subject matter of Example 2, to optionally include a speed controller coupled to the electric motor.
  • Example 4 can include, or optionally be combined with the subject matter of Example 3, to optionally include wherein the speed controller is coupled to at least one of a pressure sensor, a vacuum sensor, a temperature sensor, a fluid level sensor, and a load sensor.
  • Example 5 can include, or optionally be combined with the subject matter of Example 4, to optionally include wherein the speed controller includes a processor coupled to a memory and the processor is configured to execute instructions stored in the memory.
  • Example 6 can include, or optionally be combined with the subject matter of any one of Examples 1-5, to optionally include wherein the vacuum pump includes a seal fluid supply port coupled to a water supply line.
  • Example 7 can include, or optionally be combined with the subject matter of Example 6, to optionally include wherein the water supply line is coupled to a cooler.
  • Example 8 can include, or optionally be combined with the subject matter of any one of Examples 1-7, to optionally include wherein the intake line includes a vapor-liquid separator.
  • Example 9 can include, or optionally be combined with the subject matter of Example 8, to optionally include wherein the vapor-liquid separator is coupled to a water supply line.
  • Example 10 can include, or optionally be combined with the subject matter of any one of Examples 1-9, to optionally include an intake port coupled to the vent condenser and further include a drain port coupled to the liquid reservoir and wherein the drain port is coupled to a filter and the filter is coupled to the intake port.
  • Example 11 can include, or optionally be combined with the subject matter of Example 10, to optionally include a cooler coupled in series with the filter.
  • Example 12 can include, or optionally be combined with the subject matter of any one of Examples 10-11, to optionally include a fluid pump coupled in series with the filter.
  • Example 13 can include, or optionally be combined with the subject matter of any one of Examples 1-12, to optionally include a drain port coupled to the liquid reservoir and wherein the drain port is coupled to an input port of a collection tank.
  • Example 14 can include, or optionally be combined with the subject matter of Example 13, to optionally include wherein the collection tank includes a weir and an exit port and wherein the input port and the exit port are disposed on opposing sides of the weir.
  • Example 15 can include, or optionally be combined with the subject matter of any one of Examples 1-14, to optionally include wherein the output port is coupled to an atmospheric vent.
  • Example 16 can include, or optionally be combined with the subject matter of Example 15, to optionally include wherein the atmospheric vent includes a stack scrubber.
  • Example 17 can include, or optionally be combined with the subject matter of any one of Examples 1-16, to optionally include a bypass valve coupled in parallel with the vacuum pump.
  • Example 18 can include, or optionally be combined with the subject matter of Example 17, to optionally include wherein the gaseous mixture is removed at a rate determined by a fluid flow rate through the bypass valve.
  • Example 19 can include or use a method of operating a
  • the method can include or use producing a gaseous mixture in an upper region of a reservoir and drawing the gaseous mixture from the upper region using a vacuum.
  • the gaseous mixture is produced in an upper region of a reservoir coupled to the finisher.
  • the reservoir has a liquid level in a lower region of the reservoir.
  • the gaseous mixture is drawn from the upper region using a vacuum wherein a removal rate corresponds to a speed of a rotary shaft of a liquid ring vacuum pump.
  • Example 20 can include, or optionally be combined with the subject matter of Example 19, to optionally include operating the vacuum pump using an electric motor.
  • Example 21 can include, or optionally be combined with the subject matter of Example 19, to optionally include modulating the speed using a controller.
  • Example 22 can include, or optionally be combined with the subject matter of Example 21, to optionally include wherein modulating the speed includes executing an algorithm using a processor.
  • Example 23 can include, or optionally be combined with the subject matter of Example 22, to optionally include wherein executing the algorithm includes receiving a sensor signal corresponding to at least one of a pressure, a vacuum, a temperature, a fluid level, and a load.
  • Example 24 can include, or optionally be combined with the subject matter of Example 19, to optionally include wherein draining the gaseous mixture includes providing water to a seal fluid port of the vacuum pump.
  • Example 25 can include, or optionally be combined with the subject matter of Example 24, to optionally include wherein providing water includes cooling the water.
  • Example 26 can include, or optionally be combined with the subject matter of any one of Examples 19-25, to optionally include wherein drawing the gaseous mixture includes removing vapor from a vapor-liquid separator coupled to the upper region.
  • Example 27 can include, or optionally be combined with the subject matter of Example 26, to optionally include supplying water to the vapor-liquid separator.
  • Example 28 can include, or optionally be combined with the subject matter of any one of Examples 19-27, to optionally include removing liquid from the lower region, filtering the liquid, and returning the liquid to the upper region.
  • Example 29 can include, or optionally be combined with the subject matter of Example 28, to optionally include cooling the liquid.
  • Example 30 can include, or optionally be combined with the subject matter of any one of Examples 19-29, to optionally include removing liquid from the lower region and conveying the liquid to a collection tank.
  • Example 31 can include, or optionally be combined with the subject matter of Example 30, to optionally include draining liquid using a weir and a discharge port of the collection tank.
  • Example 32 can include, or optionally be combined with the subject matter of any one of Examples 19-31, to optionally include wherein drawing the gaseous mixture includes discharging an output of the vacuum pump to atmosphere.
  • Example 33 can include, or optionally be combined with the subject matter of any one of Examples 19-32, to optionally include bypassing the vacuum pump with a valve.
  • Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples.
  • An implementation of such methods can include code, such as microcode, assembly language code, a higher- level language code, or the like.
  • Such code can include computer readable instructions for performing various methods.
  • the code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non- volatile tangible computer-readable media, such as during execution or at other times.
  • Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Polyamides (AREA)

Abstract

La présente invention concerne un système qui est conçu pour la synthèse en continu d'un polyamide. Le système comprend un condenseur d'évacuation et une pompe à vide. Le condenseur d'évacuation est accouplé à un dispositif de terminaison de la polymérisation. Le condenseur d'évacuation comprend un réservoir de liquide et un orifice de décharge à évent au-dessus d'un niveau du réservoir de liquide. La pompe à vide est accouplée à l'orifice de décharge à évent par le biais d'une conduite d'admission. La pompe à vide comprend un orifice de sortie et un arbre rotatif. Un mélange gazeux à proximité de l'orifice de décharge à évent est retiré à un débit déterminé par une vitesse de l'arbre rotatif. La pompe à vide est conçue pour comprendre un joint à anneau liquide.
PCT/US2014/034116 2013-05-01 2014-04-15 Régulation de la pression du procédé lors de la synthèse du nylon Ceased WO2014179036A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3449220A (en) * 1964-12-23 1969-06-10 Vickers Zimmer Ag Method of separating low-molecular weight components from high-polymeric compounds by thin film vacuum distillation
FR2378059A1 (fr) * 1977-01-22 1978-08-18 Basf Ag Procede pour la preparation de polyamides de poids moleculaire eleve
US20030176625A1 (en) * 2000-03-30 2003-09-18 Heinrich Morhenn Polyamide composition and method for producing the same

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Publication number Priority date Publication date Assignee Title
DE19621088B4 (de) * 1996-05-24 2005-11-17 Karl-Heinz Wiltzer Verfahren und Vorrichtung zur kontinuierlichen Herstellung von Polyamiden
CN1061725C (zh) * 1997-03-06 2001-02-07 包素文 聚四氟乙烯多孔膜的制备方法及其产品

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3449220A (en) * 1964-12-23 1969-06-10 Vickers Zimmer Ag Method of separating low-molecular weight components from high-polymeric compounds by thin film vacuum distillation
FR2378059A1 (fr) * 1977-01-22 1978-08-18 Basf Ag Procede pour la preparation de polyamides de poids moleculaire eleve
US20030176625A1 (en) * 2000-03-30 2003-09-18 Heinrich Morhenn Polyamide composition and method for producing the same

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